Semiconductor module, portable device and method for manufacturing semiconductor module

ABSTRACT

A semiconductor module is provided, which is capable of suppressing the deterioration of reliability and improving heat radiation. The semiconductor module includes: a semiconductor substrate in which electrodes of a circuit element are formed on its surface; a re-wiring pattern connected to the electrodes to ensure large pitch of the electrodes; an electrode integrally formed with the re-wiring pattern; an insulating layer formed on a rear surface of the semiconductor substrate; a radiator formed on the insulating layer; and projections integrally formed with the radiator and penetrating the insulating layer to connect to the rear surface of the semiconductor substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromboth the prior Japanese Patent Application No. 2006-205466, filed Jul.28, 2006 and the prior Japanese Patent Application No. 2007-176296 filedJul. 4, 2007, the entire contents of which are incorporated herein byreferences.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor module, and inparticular, to a semiconductor module with a radiator.

2. Description of the Related Art

Portable electronics devices, such as mobile phones, personal digitalassistants (PDAs), digital video cameras (DVCs), and digital stillcameras (DSCs) have become increasingly sophisticated. A furtherreduction in size and weight is, however, necessary for such devices tocontinue to succeed in the market, and as such, these devices nowrequire highly integrated system LSI chips. User-friendliness andconvenience is required for these devices as well, resulting in anincreased need for highly functional high performance LSI chips.Although the highly integrated LSI chips require a large number ofinput/output ports, there is a strong desire to reduce their packagesize. To meet these conflicting requirements, the development of asemiconductor package suitable for high density board packaging ofsemiconductor parts is strongly desired. In response to such needs, avariety of packaging technologies, called chip size package (CSP)technologies, have been developed.

A CSP is formed in such a way that a semiconductor wafer (semiconductorsubstrate), in which LSI chips (circuit elements) and externalconnecting terminals connected to each LSI chip are formed on oneprincipal surface thereof, is diced into individual chips. Accordingly,the CSP, which is substantially the same size as an LSI chip, is fixedon a mounting board, resulting in a reduction in the size of themounting board on which the CSP is mounted. Therefore, the use of theCSP in a system allows the overall size of that system, such as anelectronics device, to be reduced.

Moreover, power consumption of LSI chips is increasing every year withthe associated increase in performance and functionality. This leads toan increase in the power consumption per unit volume (heat density) of aCSP (semiconductor module) with an LSI chip, resulting in a greater needfor radiation of the extra heat away from the CSP. One proposed approachto this issue is a method for effectively radiating out heat generatedin the CSP (semiconductor module) through a film which is formed on therear surface of a semiconductor substrate, which is a component of theCSP (semiconductor module). Such a film is a heat radiative film with ahigh thermal emissivity, e.g., a film containing ceramic powder, or aheat conductive film with a high thermal conductivity, e.g., copper oraluminum.

In general, a radiator, and especially a heat conductive film, used inthe CSP (semiconductor module) is subjected to internal stress in theextending direction of the radiator during the process of formation. Theinternal stress is retained in the radiator of each individual CSP afterformation. This stress causes the radiator to be separated from thesemiconductor substrate, resulting in reduced reliability of the CSP(semiconductor module). In particular, there is a high possibility ofseparation of the radiator from the semiconductor substrate when the CSP(semiconductor module) is heated.

If the development of a thinner semiconductor substrate progresses inthe future facilitating a reduction in the thickness of the CSP(semiconductor module), the remaining internal stress in the radiatorwill have a significant relative impact on the thinned semiconductorsubstrate. Accordingly, for example, the remaining internal stress inthe radiator greater than the stiffness of the semiconductor substratemay cause the CSP (semiconductor module) together with the semiconductorsubstrate to change shape and thus to warp, even if there is noseparation of the radiator from the semiconductor substrate.

SUMMARY OF THE INVENTION

The present invention has been developed in view of the foregoing factsand a general purpose thereof is to increase the heat radiation of thesemiconductor module by suppressing the reducing in reliability causedby the radiator.

To solve the aforementioned problems, a semiconductor module accordingto one embodiment of the present invention comprises: a semiconductorsubstrate with a first principal surface on which a circuit element isprovided and a second principal surface opposing the first principalsurface; an electrode provided on the first principal surface with theelectrode being electrically connected to the circuit element; aninsulating layer provided on the second principal surface; a radiatorprovided on the insulating layer; and a projection provided integrallywith the radiator, with the projection penetrating the insulating layerto connect to the second principal surface.

According to this configuration, the projection integrally formed withthe radiator reduces the internal stress of the radiator in theextending direction of the radiator, thereby suppressing the tendency ofthe radiator to warp. This in turn leads to a reduction in the problemsof separation of the radiator from the semiconductor substrate andwarpage (deformation) of the semiconductor substrate in thesemiconductor module having the radiator provided thereon when comparedwith conventional semiconductor modules. Moreover, the projection, whichconducts heat from the semiconductor substrate to the radiator toradiate out heat, improves the heat radiation of the semiconductormodule when compared with a radiator, without such a projection,connected to a semiconductor substrate through an insulating layer.Accordingly, this semiconductor module can suppress the reduction inreliability caused by the radiator and improve the heat radiation.

In the foregoing configuration, it is preferable that a plurality of theprojections be arranged on the radiator in a matrix array in plane. Thisarrangement effectively reduces the internal stress of the radiator,thus further increasing the reliability of the semiconductor module.

In the foregoing configuration, it is preferable that the tops of theprojections be embedded in the semiconductor substrate. The tips of theprojections embedded in the semiconductor substrate prevent relativedisplacement between the semiconductor substrate and the radiator evenwhen a shearing stress is applied therebetween, thus further increasingthe reliability of the connection between the semiconductor substrateand the radiator.

In the foregoing configuration, a gap may be formed between theinsulating layer and the radiator, except for the projection.

Also in the foregoing configuration, the radiator may be patterned so asto selectively cover a specific region of the semiconductor substrate.Part of the pattern may be used as a wiring platform. This in turnallows part of the radiator to be used as a wiring platform, improvingthe design freedom of the wiring and thus reducing the size of thesemiconductor module. The insulating layer may be made of an insulatingresin which is a material that undergoes plastic flow when placed underpressure, and the projections may penetrate the insulating layer bycompression-bonding the radiator onto the insulating layer to thermallyconnect the projections to the circuit element.

Another embodiment of the present invention is a portable device. Theportable device comprises a casing and any one of the above-mentionedsemiconductor modules housed in the casing. In the portable devicehaving the above-detailed configuration, the radiator of thesemiconductor module may come into contact with an inner surface of thecasing.

Another embodiment of the present invention is a method formanufacturing a semiconductor module. The method comprises: preparing asemiconductor substrate provided with a circuit element on a firstprincipal surface; forming an insulating layer having an opening on asecond principal surface of the semiconductor substrate; and forming aradiator integrally provided with a projection by filling the openingwith a metal and by coating the opening and an upper portion of theinsulating layer with the metal.

Yet another embodiment of the present invention is a method formanufacturing a semiconductor module. The method comprises: preparing asemiconductor substrate provided with a circuit element on a firstprincipal surface; forming an insulating layer on a second principalsurface of the semiconductor substrate; and compression-bonding aradiator integrally provided with a projection to the second principalsurface of the semiconductor substrate and bringing the projectionpenetrating the insulating layer into contact with the second principalsurface of the semiconductor substrate. In the method for manufacturinga semiconductor module detailed above, the insulating layer may beadhesive.

In the method for manufacturing a semiconductor module detailed above,the insulating layer may be made of an insulating resin which is amaterial that undergoes plastic flow when placed under pressure. Themethod for manufacturing a semiconductor module may further comprisepatterning the radiator by selectively removing a portion of theradiator. In the method for manufacturing a semiconductor moduledetailed above, the radiator that is compression-bonded to the secondsurface of the semiconductor substrate may be patterned in advance. Inthe method for manufacturing a semiconductor module detailed above, theinsulating layer may be adhesive.

It is to be noted that any arbitrary combination or rearrangement of theabove-described structural components and so forth are all effective asand encompassed by the present embodiments.

Moreover, this summary of the invention does not necessarily describeall necessary features so that the invention may also be sub-combinationof these described features.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, withreference to the accompanying drawings which are meant to be exemplary,not limiting, and wherein like elements are numbered alike in severalFigures, in which:

FIG. 1 is a schematic cross-sectional view of a semiconductor moduleaccording to a first embodiment of the present invention;

FIGS. 2A and 2B are plan views showing an arrangement of projectionsprovided on a radiator as shown in FIG. 1;

FIGS. 3A to 3D are schematic cross-sectional views showing amanufacturing process of the semiconductor module according to the firstembodiment of the present invention;

FIGS. 4A to 4C are schematic cross-sectional views showing themanufacturing process of the semiconductor module according to the firstembodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of a semiconductor moduleaccording to a second embodiment of the present invention;

FIGS. 6A and 6D are schematic cross-sectional views showing a method forforming a copper plate integrally formed with projections according tothe second embodiment of the present invention;

FIGS. 7A to 7D are schematic cross-sectional views showing amanufacturing process of the semiconductor module according to thesecond embodiment of the present invention;

FIGS. 8A to 8D are schematic cross-sectional views showing themanufacturing process of the semiconductor module according to thesecond embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view of a semiconductor moduleaccording to a third embodiment of the present invention;

FIG. 10 is a schematic cross-sectional view of a semiconductor moduleaccording to a fourth embodiment of the present invention;

FIG. 11 is a schematic cross-sectional view of a semiconductor moduleaccording to a fifth embodiment of the present invention;

FIG. 12 is a schematic cross-sectional view of a mobile phone accordingto a sixth embodiment of the present invention; and

FIG. 13 is a partial cross-sectional view (a cross-sectional view of afirst casing) of the mobile phone shown in FIG. 12.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described by reference to the preferredembodiments. This does not intend to limit the scope of the presentinvention, but to exemplify the invention.

Exemplified embodiments of the present invention will be described belowwith reference to the drawings. Note that the same components as thosein all drawings are denoted by the same reference characters, and theirdescriptions will not be repeated accordingly.

First Embodiment

FIG. 1 is a schematic cross-sectional view of a semiconductor moduleaccording to a first embodiment of the present invention. Thesemiconductor module according to the first embodiment will be describedwith reference to FIG. 1.

A semiconductor substrate 1 is, for example, a p-silicon substrate,which has a surface S (lower surface) on which a circuit element 2, suchas a predetermined electrical circuit, is formed by a techniquewell-known to those skilled in the art and on which electrodes 2 a ofthe circuit element 2 are formed (circumferentially). A protective film3 is formed on all regions of the surface of the semiconductor substrate1 except the electrodes 2 a. A re-wiring pattern 4 connected to exposedfaces of the electrodes 2 a and electrodes 4 a which are integrallyprovided with the re-wiring pattern 4 are formed to ensure that thepitch of the electrodes 2 a is sufficiently large. Note that thesemiconductor substrate 1, the circuit element 2, the surface S, and theelectrodes 4 a are examples of the “semiconductor substrate,” the“circuit element,” the “first principal surface,” and the “electrodes”of the present invention, respectively.

An insulating layer 7 is formed on the rear surface R (upper surface) ofthe semiconductor substrate 1. The insulating layer 7 is an epoxy resinbased film, and is, for example, approximately 100 μm thick. The epoxyresin based insulating layer 7 may be a film of tangled glass fibersimpregnated with resin or a film to which fillers with a diameter in therange of approximately 2 μm to 10 μm are added. The fillers may be, forexample, alumina (Al₂O₃), silica (SiO₂), aluminum nitride (AlN), siliconnitride (SiN), or boron nitride (BN). Such fillers preferably have amass filling factor in the range of approximately 30% to 80%. It isdesirable that the insulating layer 7 be adhesive in order to prevent aradiator 8 described later from being separated from the semiconductorsubstrate 1.

A plurality of openings 7 a are formed in the insulating layer 7 atpredetermined intervals, e.g., approximately 300 μm apart. The openings7 a have a diameter of approximately 60 μm and pass through theinsulating layer 7 in the thickness direction. These openings 7 a arearranged in a matrix array over the plane of the radiator 8 toeffectively reduce the internal stress of the radiator 8. The matrixarray is, for example, a square lattice or a honeycomb lattice (being ahexagonal grid and associated centers). Note that the rear surface R andthe insulating layer 7 are examples of the “second principal surface”and the “insulating layer” of the present invention, respectively.

The radiator 8 is formed on the insulating layer 7. Projections 8 aformed in the openings 7 a, which pass through the insulating layer 7,are integrally provided with the radiator 8. The radiator 8 and theprojections 8 a are formed of, for example, a metal film such as copperor aluminum. The radiator 8 is, for example, approximately 100 μm thick.The radiator 8 covers the majority of the rear surface R of thesemiconductor substrate 1. The tops of the projections 8 a does,however, come into direct contact with the rear surface R of thesemiconductor substrate 1. This arrangement allows the projections 8 ato be thermally connected to the semiconductor substrate 1, and thus theprojections 8 a conduct heat from the semiconductor substrate 1 towardthe radiator 8, so that the heat of the semiconductor substrate 1 iseffectively radiated away. The projections 8 a each have a round sectionwith a diameter of approximately 60 μm, and correspond to the respectiveopenings 7 a. Accordingly, the projections 8 a are arranged on theradiator 8 in a matrix array in plane, like the openings 7 a.Specifically, the projections 8 a are arranged in a square lattice, asshown in FIG. 2A, or in a honeycomb lattice, as shown in FIG. 2B, atequal intervals (interval X). Note that the radiator 8 and theprojections 8 a are examples of the “radiator” and the “projections” ofthe present invention, respectively.

Manufacturing Method

FIGS. 3A to 3D and 4A to 4C are cross-sectional views illustrating theprocess of manufacturing the semiconductor module according to the firstembodiment shown in FIG. 1. The process of manufacturing thesemiconductor module according to the first embodiment will now bedescribed with reference to FIGS. 1, 3A to 3D, and 4A to 4C.

As shown in FIG. 3A, a semiconductor wafer on which the semiconductorsubstrates 1 are arranged in a matrix array is prepared. Eachsemiconductor substrate 1 includes the electrodes 2 a of the circuitelement 2 and the protective film 3, which are formed on the surface S.The semiconductor wafer is sectioned into a plurality of semiconductormodule regions 6 by a plurality of scribe lines 5. Each of thesemiconductor module regions 6 is a region on which the semiconductormodule described above is formed. Specifically, the circuit element 2,such as a predetermined electrical circuit, is formed on the surface S(lower surface) by a technique well-known to those skilled in the art,and the electrodes 2 a are formed on or around the circuit element 2.The electrodes 2 a are generally made of a metal such as aluminum (Al).The protective film 3 is formed on all regions of the surface S of thesemiconductor substrate 1 except the electrodes 2 a in order to protectthe semiconductor substrate 1. The protective film 3 is made of, forexample, silicon dioxide film (SiO₂) or silicon nitride film (SiN).

As shown in FIG. 3B, the re-wiring pattern 4 made of copper (Cu) and theelectrodes 4 a which are integrally provided with the re-wiring pattern4 are formed so as to be connected to the exposed faces of theelectrodes 2 a to ensure that the pitch of the electrodes 2 a is largeenough. In this instance, the re-wiring pattern 4 and the electrodes 4 aare formed in a desired pattern in such a manner that the processes ofresist pattern forming, copper plating, and resist stripping arerepeated twice. Integrally forming the electrodes 4 a with the re-wiringpattern 4 eliminates the need for connection between different materialsin the path from the electrodes 2 a of the circuit element 2 to theelectrodes 4 a. Accordingly, this configuration has less potential foran adverse effect such as disconnection even when thermal stress isapplied due to variations in temperature and the like during use of thesemiconductor module.

As shown in FIG. 3C, the insulating layer 7 with a copper foil 8 z isthermocompression-bonded to the rear surface R (upper surface) of thesemiconductor substrate 1 (semiconductor wafer) under vacuum or lowpressure. The insulating layer 7 is, for example, approximately 100 μmthick, and the copper foil 8 z is, for example, approximately 10 μmthick. The insulating layer 7 is made of the same material as thatdescribed above. The insulating layer 7, when formed from a film with ahigh heat conductivity such as a film of tangled glass fibersimpregnated with resin or a film to which fillers are added, conductsheat of the semiconductor substrate 1 to the radiator 8, therebyimproving the heat radiation of the semiconductor module.

As shown in FIG. 3D, parts of the copper foil 8 z, which are located onthe regions of the openings 7 a (see FIG. 1), are removed byphotolithography and etching techniques, so that the regions of theinsulating layer 7 corresponding to the openings 7 a are exposed.

After that, as show in FIG. 4A, the regions extending from the exposedface of the insulating layer 7 to the rear surface R of thesemiconductor substrate 1 are removed by irradiation using a carbondioxide gas laser or a UV laser directed from above the copper foil 8 z.Accordingly, the openings 7 a, which have a diameter of approximately 60μm and pass through the insulating layer 7, are formed in the insulatinglayer 7.

As shown in FIG. 4B, copper is plated to a thickness of approximately 1μm on the surface of the copper foil 8 z and the inner surface of theopenings 7 a by nonelectrolytic plating. Following this, copper isplated on the surface of the copper foil 8 z and the inside of theopenings 7 a by electrolytic plating. In this embodiment, an inhibitorand a promoter are added to the plating solution so that the surface ofthe copper foil 8 z adsorbs the inhibitor and the inner surface of theopenings 7 a adsorbs the promoter. This adsorption allows copper to bemore thickly plated on the inner surface of the openings 7 a, thereforefilling the openings 7 a with copper. Consequently, as shown in FIG. 4B,the radiator 8 with a thickness of approximately 100 μm above theinsulating layer 7 is formed to cover the majority of the semiconductorsubstrate 1 (semiconductor wafer), and the projections 8 a are embeddedin the openings 7 a. In other words, the projections 8 a are integrallyformed with the radiator 8 and penetrate the insulating layer 7 so thatthe tip of the projections 8 a come into direct contact with the rearsurface R of the semiconductor substrate 1 (semiconductor wafer).

As shown in FIG. 4C, the semiconductor wafer is diced from above therear surface R (upper surface) of the semiconductor wafer along thescribe lines 5 for sectioning the semiconductor module regions 6 inorder to obtain individual semiconductor modules having the same outsidedimension as that of the semiconductor substrate 1. After that, anyresidue caused by dicing is removed by rinsing the semiconductor modulewith a chemical. At this time, the small amount of the insulating layer7 that is exposed at the side wall of the semiconductor module isremoved, so that the surface area of the radiator 8 increases.Accordingly, the heat radiation of the radiator 8 is improved comparedwith the case without rinsing with the chemical. If the side surface ofthe radiator 8 and the side surface of the semiconductor substrate 1 areirregularly processed to increase their surface areas, the heatradiation at the irregular surfaces increases and thus the heatradiation of the semiconductor module is improved.

The semiconductor module according to the first embodiment shown in FIG.1 is manufactured by the above-detailed processes.

The semiconductor module and the manufacturing method therefor accordingto the first embodiment as described above have the followingadvantages:

(1) The warpage of the radiator 8 is suppressed because the projections8 a integrally formed with the radiator 8 reduce the internal stress ofthe radiator 8 in the extending direction of the radiator 8. This inturn leads to a reduction in the problems of separation of the radiator8 from the semiconductor substrate 1 and warpage (deformation) of thesemiconductor substrate 1 in the semiconductor module having theradiator 8 provided on the semiconductor substrate 1 when compared withconventional semiconductor modules. Moreover, the projections 8 a, whichconduct heat from the semiconductor substrate 1 toward the radiator 8 toradiate out the heat, improve the heat radiation of the semiconductormodule when compared with a radiator without such projections which isconnected to a semiconductor substrate through an insulating layer.Accordingly, this semiconductor module can suppress the reduction inreliability caused by the radiator 8 and improve the heat radiation.

(2) The projections 8 a are arranged on the radiator 8 in a matrix arrayin plane to effectively reduce the internal stress of the radiator 8,thus further increasing the reliability of the semiconductor module.

(3) The projections 8 a, which connect the radiator 8 and thesemiconductor substrate 1, conduct heat from the semiconductor substrate1 toward the radiator 8. Hence, the heat may cause the radiator 8 toextend. However, the projections 8 a reduce an effect of the extensionon the semiconductor substrate 1, i.e., a difference in extended amountbetween the radiator 8 and the semiconductor substrate 1, thus improvingthe reliability of the semiconductor module when compared with theconventional semiconductor modules.

(4) The radiator 8 and the other elements are collectively formed on thesemiconductor wafer before the semiconductor wafer is sectioned intoindividual semiconductor modules, thereby reducing the manufacturingcost of each semiconductor module when compared with the case where theradiator 8 and the other elements are formed for each semiconductormodule.

Second embodiment

FIG. 5 is a schematic cross-sectional view of a semiconductor moduleaccording to a second embodiment of the present invention. Thesemiconductor module according to the second embodiment will bedescribed with reference to FIG. 5.

A semiconductor substrate 11 is, for example, a p-silicon substrate,which has a surface S2 (lower surface) on which a circuit element 12,such as a predetermined electrical circuit, is formed by a techniquewell-known to those skilled in the art and on which electrodes 12 a ofthe circuit element 12 are formed (circumferentially). A protective film13 is formed on all regions of the surface of the semiconductorsubstrate 11 except the electrodes 12 a. Note that the semiconductorsubstrate 11, the circuit element 12, and the surface S2 are examples ofthe “semiconductor substrate,” the “circuit element,” and the “firstprincipal surface” of the present invention, respectively.

An insulating layer 17 is formed on a rear surface R2 (upper surface) ofthe semiconductor substrate 11, and is, for example, approximately 100μm thick. The insulating layer 17 is made from a material that undergoesplastic flow when placed under pressure. A material that undergoesplastic flow when placed under pressure includes an epoxy-basedthermosetting resin. The epoxy-based thermosetting resin used as theinsulating layer 17 may be a material which has a viscosity of 1 kpa·sat a temperature of 160° C. and a pressure of 8 MPa, for example. Theviscosity of the resin decreases to about ⅛ when the material ispressurized to 15 MPa at a temperature of 160° C. when compared with thecase of a resin not being pressurized. Conversely, B-stage epoxy resinunder the condition of the glass transition temperature Tg or lessbefore thermal cure has a viscosity as small as that when the resin isnot pressurized, and there is no change in viscosity even if the resinis pressurized. Note that the rear surface R2 and the insulating layer17 are examples of the “second principal surface” and the “insulatinglayer” of the present invention, respectively.

A radiator 18 is formed on the insulating layer 17, and is integrallyprovided with projections 18 a which penetrate the insulating layer 17.

The radiator 18 and the projections 18 a are made of, for example, ametal film such as copper. The radiator 18 is, for example,approximately 100 μm thick, and the projections 18 a are, for example,approximately 100 μm in height. As a result, the distance between thesurface of the radiator 18 and the tip of the projection 18 a whichcontacts to the rear surface R2 is, for example, approximately 200 μm.The radiator 18 is provided to cover the entire rear surface R2 of thesemiconductor substrate 11. The projections 18 a each have a roundsection and each comprises a top portion 18 a 1 and a side portion 18 a2. The tip portion 18 a 1 is in parallel with the contact face of thesemiconductor substrate 11. The side portion 18 a 2 is formed so thatthe projection 18 a tapers toward the top portion 18 a 1. The tops (topportion 18 a 1) and the bases of the projections 18 a are approximately40 μmφ and approximately 60 μmφ in diameter, respectively. Moreover, aplurality of the projections 18 a is arranged on the radiator 18 in amatrix array in plane. The matrix array may include, for example, asquare lattice or a honeycomb lattice, as shown in FIGS. 2A and 2B ofthe above-described first embodiment. The projections 18 a are formed atpredetermined intervals, for example, approximately 300 μm. The tops(top portion 18 a 1) of the projections 18 a are formed so as to comeinto direct contact with the rear surface R2 of the semiconductorsubstrate 11. This arrangement allows the projections 18 a to bethermally connected to the semiconductor substrate 11, and thus heat isconducted away from the semiconductor substrate 11 toward the radiator18 through the projections 18 a, so that the heat of the semiconductorsubstrate 11 is effectively radiated away. Note that the radiator 18 andthe projections 18 a are examples of the “radiator” and the“projections” of the present invention, respectively.

In the surface S2 (lower surface) of the semiconductor substrate 11, theinsulating layer 19 is formed on the electrodes 12 a and the protectivefilm 13 to ensure that the pitch of the electrodes 12 a is sufficientlylarge. Projecting conductors 14 a and re-wiring patterns 14 are formed.In this instance, the projecting conductors 14 a penetrate theinsulating layer 19 so as to come into contact with the exposed faces ofthe electrodes 12 a. The re-wiring patterns 14 are integrally providedwith the conductors 14 a. Electrodes (being solder bumps) 20 areprovided on the outer side (being lower surface) of the re-wiringpatterns 14 where the electrodes 12 a are connected through theconductors 14 a. The electrodes 20 are one example of the “electrodes”of the present invention.

The insulating layer 19 is made of the same material as the insulatinglayer 17, and is, for example, approximately 60 μm thick.

The re-wiring patterns 14 are formed on the insulating layer 19, andintegrally provided with the projecting conductors 14 a which penetratethe insulating layer 19. The re-wiring patterns 14 and the conductors 14a are made of, for example, a metal such as copper, which has beenrolled out. The rolled copper exhibits excellent mechanical strength andthus is suitable as a re-wiring material, when compared with a copperfilm formed by a plating process. The re-wiring patterns 14 are, forexample, approximately 30 μm thick, and the conductors 14 a are, forexample, approximately 60 μm in height (thickness). The conductors 14 aeach have a round section and each comprises a top portion 14 a 1 and aside portion 14 a 2. The top portion 14 a 1 is in parallel with thecontact face of the electrode 12 a of the semiconductor substrate 11.The side portion 14 a 2 is formed so that the conductor 14 a taperstoward the top portion 14 a 1. The tops (top portion 14 a 1) and thebases of the conductors 14 a are approximately 40 μmφ and approximately60 μmφ in diameter, respectively. Moreover, the conductors 14 a arearranged at the positions corresponding to the electrodes 12 a,respectively. The tops (top portion 14 a 1) of the conductors 14 a areformed so as to come into direct contact with the electrodes 12 a of thesemiconductor substrate 11, and thus electrically connect the electrodes12 a and the re-wiring patterns 14.

Manufacturing Process

FIGS. 6A to 6D are schematic cross-sectional views illustrating onemethod for forming a copper plate being integrally formed withprojections. FIGS. 7A to 7D and FIGS. 8A to 8D are schematiccross-sectional views illustrating a manufacturing process of thesemiconductor module according to the second embodiment as shown in FIG.5. The manufacturing process of the semiconductor module according tothe second embodiment will now be described with reference to FIG. 5 toFIG. 8D.

As shown in FIG. 6A, a copper plate 18 z which has a thickness that isat least greater than the combined height of the projections 18 a andthe radiator 18 is prepared. In this instance, the copper plate 18 z isapproximately 300 μm thick. Rolled copper is used as the copper plate 18z.

As shown in FIG. 6B, a resist mask 21 is formed in the projectionformation area using a standard lithography method. The projectionformation area is as shown in the above-mentioned figures.

As shown in FIG. 6C, the projections 18 a of the predetermined patternare formed into the copper plate 18 z by etching with the resist mask 21used as a mask. Adjusting the etching conditions allows the formation ofthe side portion 18 a 2 in which the projection 18 a tapers toward thetop portion 18 a 1. In this instance, the projections 18 a areapproximately 100 μm in height, and the tops (top portion 18 a 1) andthe bases of the projections 18 a are approximately 40 μmφ andapproximately 60 μmφ in diameter, respectively.

As shown in FIG. 6D, the resist mask 21 is then removed. As a result ofthis process, the projections 18 a, each having the top portion 18 a 1and the side portion 18 a 2 formed so that the projection 18 a taperstoward the top portion 18 a 1, are formed in the copper plate 18 z. Ametal mask such as silver (Ag) may be used in place of the resist mask21. In this instance, the metal mask can ensure a high etchingselectivity with respect to the copper plate 18 z, thereby making theprojections 18 a more finely patterned.

The copper plate 14 z integrally formed with the projecting conductors14 a is formed by the method described above. As a result, theconductors 14 a, each having a top portion 14 a 1 and a side portion 14a 2 formed so that the conductor 14 a tapers toward the top portion 14 a1, are formed. In this instance, the projecting conductors 14 a areapproximately 60 μm in height, and the tops (top portion 14 a 1) and thebases of the conductors 14 a are approximately 40 μmφ and approximately60 μmφ in diameter, respectively.

These copper plates 18 z and 14 z, being manufactured as detailed above,are separately prepared, and are then used for the manufacturing processfor the semiconductor module according to the second embodiment, whichwill be described below.

As shown in FIG. 7A, the semiconductor wafer, in which the semiconductorsubstrates 11 with the electrodes 12 a and the protective film 13 on thesurface S2 thereof are arranged in a matrix array, is first prepared. Itshould be appreciated that the semiconductor wafer has been sectionedinto a plurality of semiconductor module regions 16 by a plurality ofscribe lines 15. Each of the semiconductor module regions 16 is a regionwhere the semiconductor module described above is to be formed.Specifically, a semiconductor substrate 11 is, for example, a p-siliconsubstrate or other semiconductor wafer. The substrate 11 has a surfaceS2 (lower surface) on which a circuit element 12, such as apredetermined electrical circuit, is formed and electrodes 12 a areformed circumferentially with respect to the circuit element 12 or abovethe element 12 by a technique well-known to those skilled in the art.The electrodes 12 a are generally made of a metal such as aluminum (Al).The protective film 13 is formed on all regions of the surface S2 of thesemiconductor substrate 11 except the electrodes 12 a in order toprotect the semiconductor substrate 11. The protective film 13 is madeof, for example, silicon dioxide film (SiO₂) or silicon nitride film(SiN).

As shown in FIG. 7B, the insulating layer 17 is located between thesemiconductor substrate 11 and the copper plate 18 z integrally formedwith the projections 18 a. This combination is formed on the rearsurface R2 (upper surface) of the semiconductor wafer (semiconductorsubstrate 11). The thickness of the insulating layer 17 is approximately100 μm, which is the same as the height of the projections 18 a. Theinsulating layer 19 is located between the semiconductor substrate 11and the copper plate 14 z integrally formed with the projectingconductors 14 a. This combination is formed on the surface S2 (lowersurface) of the semiconductor wafer (semiconductor substrate 11). Thethickness of the insulating layer 19 is approximately 60 μm, which isthe same as the height of the conductors 14 a. The copper plate 18 z,which is integrally formed with the projections 18 a, and the copperplate 14 z, which is integrally formed with the projecting conductors 14a, are formed as described above. The insulating layers 17 and 19 arepreferably adhesive, so that the radiator 18 and the re-wiring pattern14 described later are prevented from being separated from thesemiconductor substrate 11.

As shown in FIG. 7C, the copper plate 18 z, the insulating layer 17, thesemiconductor substrate 11, the insulating layer 19, and the copperplate 14 z, with these elements being sandwiched as described above, areintegrated by compression molding with a pressure device. The pressworking is performed at a pressure of approximately 15 MPa and atemperature of 180° C. This press working makes the projections 18 apenetrate the insulating layer 17, so that the projections 18 a areconnected to the rear surface R2 of the semiconductor substrate 11. Atthe same time, the projecting conductors 14 a penetrate the insulatinglayer 19, so that the conductors 14 a are electrically connected to theelectrodes 12 a of the semiconductor substrate 11. The side portion 18 a2 (side portion 14 a 2), which is formed so that the projection 18 a(conductor 14 a) tapers toward the top portion 18 a 1 (top portion 14 a1), allows the projections 18 a (conductors 14 a) to smoothly penetratethe insulating layer 17 (insulating layer 19).

The pressure at the press working lowers the viscosity of the insulatinglayer 17 (insulating layer 19), thereby causing plastic flow of theinsulating layer 17 (insulating layer 19). As a result, the insulatinglayer 17 (insulating layer 19) is pushed out of the interface betweenthe projections 18 a (conductors 14 a) and the rear surface R2 of thesemiconductor substrate 11 (electrodes 12 a of the semiconductorsubstrate 11), so that part of the insulating layer 17 (insulating layer19) is hard to remain in the interface.

As shown in FIG. 7D, the entire copper plate 18 z is etched so as tohave the same thickness as the radiator 18. The radiator 18 in thepresent embodiment is approximately 100 μm thick. Accordingly, theradiator 18, which is integrally provided with the projections 18 apenetrating the insulating layer 17, is formed on the insulating layer17.

As shown in FIG. 8A, the entire copper plate 14 z is then etched so asto have the same thickness as the re-wiring pattern 14. The re-wiringpattern 14 in the present embodiment is approximately 30 μm thick.

As shown in FIG. 8B, the copper plate 14 z is etched into the re-wiringpattern 14 by photolithography and etching techniques.

As shown in FIG. 8C, electrodes 20 (being solder balls), which functionas external connecting terminals of the re-wiring pattern 14 to whichthe electrodes 12 a are connected through the conductors 14 a, areformed by the solder print method. Specifically, the electrodes 20(being solder balls) are formed by printing, using a screen mask on theportions desired, a “solder paste” made of a paste of resin and a soldermaterial, and by heating at the solder melting point. Alternatively,flux may be applied on the re-wiring pattern 14 beforehand, and solderballs are then mounted directly onto the re-wiring pattern 14.

As shown in FIG. 8D, the semiconductor wafer is diced from above therear surface R2 (upper surface) of the semiconductor wafer along thescribe lines 15 for sectioning the semiconductor module regions 16 inorder to obtain individual semiconductor modules having the same outsidedimension as that of the semiconductor substrate 11. After that, anyresidue caused by dicing is removed by rinsing the semiconductor modulewith a chemical.

The semiconductor module according to the second embodiment, as shown inFIG. 5, is manufactured by the above-detailed processes.

The semiconductor module and the manufacturing method therefor accordingto the second embodiment as described above have the followingadvantages:

(5) The warpage of the radiator 18 is suppressed because the projections18 a integrally formed with the radiator 18 reduce the internal stressof the radiator 18 in the extending direction of the radiator 18. Thisin turn leads to a reduction in the problems of separation of theradiator 18 from the semiconductor substrate 11 and warpage(deformation) of the semiconductor substrate 11 in the semiconductormodule having the radiator 18 provided on the semiconductor substrate 11when compared with the conventional semiconductor modules. Moreover, theprojections 18 a, which conduct heat from the semiconductor substrate 11toward the radiator 18 to radiate out the heat, improve the heatradiation of the semiconductor module, when compared with a radiatorwithout such projections which is connected to a semiconductor substratethrough the insulating layer. Accordingly, this semiconductor module cansuppress the reduction in reliability caused by the radiator 18 andimprove the heat radiation.

(6) The projections 18 a are arranged on the radiator 18 in a matrixarray in plane to effectively reduce the internal stress of the radiator18, thus further increasing the reliability of the semiconductor module.

(7) The projections 18 a, which connect the radiator 18 and thesemiconductor substrate 11, conduct heat from the semiconductorsubstrate 11 toward the radiator 18. Hence, the heat may cause theradiator 18 to extend. However, the projections 18 a reduce an effect ofthe extension on the semiconductor substrate 11, i.e., a difference inextended amount between the radiator 8 and the semiconductor substrate1, thus improving the reliability of the semiconductor module whencompared with the conventional semiconductor modules.

(8) The copper plate 18 z (being the radiator 18), which is integrallyformed with the projections 18 a, is manufactured in a separate process,thereby allowing only non-defective ones to be used. Moreover, theprojections 18 a, which are self-aligned and penetrate the insulatinglayer 17, are formed only by one process (press working). Accordingly,it is possible to improve the production yield of the radiatorintegrated with the projections when compared with the first embodiment.Therefore, it is possible to reduce the cost of a semiconductor module.

(9) The re-wiring pattern 14, which is integrated with the conductors 14a, is formed on the surface S2 (lower surface) of the semiconductorsubstrate 11, so that an effect of the stress of the radiator 18 on thesemiconductor substrate 11, i.e., the stress of the radiator 18 reducedby the projections 18 a, is balanced by an effect of the stress of there-wiring pattern 14 on the semiconductor substrate 11, i.e., the stressof the re-wiring pattern 14 reduced by the conductors 14 a. Accordingly,the balance of stress as well as the reduced internal stress of theradiator 18 by the projections 18 a suppresses the warpage of the entiresemiconductor module, thus further increasing the reliability of thesemiconductor module.

(10) The copper plates 18 z and 14 z, which are the bases of theradiator 18 and the re-wiring pattern 14, respectively, aresimultaneously subjected to press working, thereby reducing andsuppressing the effect of the internal stress on the semiconductormodule during the following manufacturing process. Accordingly, it ispossible to improve the production yield of the semiconductor module,and thus to reduce the cost of the semiconductor module.

(11) Since the radiator 18, the re-wiring pattern 14, and the otherelements are collectively formed in the semiconductor wafer before thesemiconductor wafer is sectioned into individual semiconductor modules,the manufacturing cost of the semiconductor module can be reduced whencompared with the case where the radiator 18, the re-wiring pattern 14,and the other elements are individually formed on each semiconductormodule.

Third Embodiment

FIG. 9 is a schematic cross-sectional view of a semiconductor moduleaccording to a third embodiment of the present invention. The thirdembodiment differs from the second embodiment in that parts of theprojections 18 a are embedded in the rear surface R2 (upper surface) ofthe semiconductor substrate 11. The other configuration is the same asthat of the second embodiment.

The configuration in which the projections 18 a are embedded is achievedby forming recesses 22 in advance in regions to be connected with theprojections 18 a by photolithography and etching techniques, on the rearsurface R2 (upper surface) of the semiconductor wafer (semiconductorsubstrate 11) prepared as shown in FIG. 7A. The recesses 22 are taperedsuitable for portions in which the projections 18 a are embedded. Therecesses 22 each have a depth D of, for example, approximately 20 μm,and the projections 18 a are formed higher accordingly.

The semiconductor module and the manufacturing method therefor accordingto the third embodiment have the advantages (5) to (11) described aboveand the following advantages:

(12) The top portions of the projections 18 a are embedded in thesemiconductor substrate 11, thereby increasing the contact areas betweenthe semiconductor substrate 11 and the projections 18 a and thusimproving adhesiveness therebetween. Accordingly, it is possible tofurther increase the connection reliability between the semiconductorsubstrate 11 and the radiator 18 (projections 18 a). The increasedcontact areas between the semiconductor substrate 11 and the projections18 a allow the heat from the semiconductor substrate 11 to beeffectively conducted to the projections 18 a, thus further increasingthe heat radiation of the semiconductor module.

(13) The top portions of the projections 18 a embedded in thesemiconductor substrate 11 prevent relative displacement between thesemiconductor substrate 11 and the radiator 18 even when a displacementstress is applied to between the semiconductor substrate 11 and theradiator 18, thus further increasing connection reliability between thesemiconductor substrate 11 and the radiator 18.

(14) The recesses 22, which are formed in the rear surface R2 (uppersurface) of the semiconductor substrate 11, allow self-alignment of thecopper plate 18 z, which is integrally formed with the projections 18 a,in the press working, thereby easily manufacturing the semiconductormodule.

Fourth Embodiment

FIG. 10 is a schematic cross-sectional view of a semiconductor moduleaccording to a fourth embodiment of the present invention. The fourthembodiment differs from the second embodiment in that there is a gap Hbetween the insulating layer 17 and the radiator 18. The otherconfiguration is the same as that of the second embodiment. The gap Hmay be formed at least partially between the insulating layer 17 and theradiator 18 except the projections 18 a. The gap H may open to theoutside air in the direction crossing the semiconductor module. When thesemiconductor module generates heat, this configuration allows the hotair in the gap H to be exchanged with the outside air, thereby improvingthe heat radiation of the semiconductor module. The gap H may be aclosed space, so that it serves as a shock absorber with respect to astrain applied to the semiconductor module from outside to reduce damageto the semiconductor module.

Such a configuration is achieved by forming the insulating layer 17thinner than the projections 18 a during the press working of the copperplate 18 z integrally formed with the projections 18 a. The insulatinglayer 17 is, for example, approximately 75 μm thick, and the gap Hbetween the insulating layer 17 and the radiator 18 is approximately 25μm, accordingly.

The semiconductor module and the manufacturing method therefor accordingto the fourth embodiment have the advantages (5) to (11) described aboveand the following advantages:

(15) The gap H between the insulating layer 17 and the radiator 18 leadsto an increase in contact areas between the radiator 18 and the outsideenvironment (atmosphere), thus further increasing the heat radiation ofthe semiconductor module.

Fifth Embodiment

FIG. 11 is a schematic cross-sectional view of a semiconductor moduleaccording to a fifth embodiment of the present invention. The fifthembodiment differs from the second embodiment in that the thicknesses ofthe insulating layer 17 and the radiator 18 are the same as those of theinsulating layer 19 and the re-wiring pattern 14, respectively, whichare provided on the surface S2 (lower surface) of the semiconductorsubstrate 11, and then the radiator 18 is patterned. The otherconfiguration is the same as that of the second embodiment. It should benote that the thicknesses of the insulating layer 17 and the radiator 18are not required to be the same as those of the opposing elements if theelements on two sides of the semiconductor substrate 11 have the samethermal expansion coefficient.

Such a configuration is achieved by processing the radiator 18 into apredetermined pattern by photolithography and etching techniques beforethe radiator 18 and the semiconductor substrate 11 arecompression-bonded, following the process shown in FIG. 7A.Alternatively, the radiator 18, which has been half-etched, may becompression-bonded to the semiconductor substrate 11 and thenfull-etched.

Alternatively, such a configuration is achieved by processing theradiator 18 into a predetermined pattern by photolithography and etchingtechniques, following the process shown in FIG. 7B.

The semiconductor module and the manufacturing method therefor accordingto the fifth embodiment have the advantages (5) to (11) described aboveand the following advantages:

(16) Parts of the radiator 18 which is processed into a predeterminedpattern are usable as a wiring, for example, ground line, so that designfreedom of wiring is improved and thus a small semiconductor module canbe provided.

Sixth Embodiment

A portable device including any one of the semiconductor modulesaccording to the above-described embodiments will now be described. Amobile phone is exemplified as the portable device, but examples of theportable device may include a personal digital assistant (PDA), adigital video camera (DVC), a music player, and a digital still camera(DSC).

FIG. 12 is a schematic cross-sectional view of a mobile phone accordingto a sixth embodiment of the present invention. A mobile phone 110 has astructure including a first casing 112 and a second casing 114 which areconnected by a movable portion 120. The first casing 112 and the secondcasing 114 are rotatable about the movable portion 120 which serves as arotating shaft. The first casing 112 is provided with a display 118, onwhich information such as characters and images are displayed, and aspeaker 124. The second casing 114 is provided with a console portion122, such as operation buttons, and a microphone 126. In the presentembodiment, the semiconductor module according to the second embodiment(see FIG. 5) is installed in the mobile phone 110. Thus, thesemiconductor module installed in the mobile phone is to be used as, forexample, a power supply circuit for driving the other circuits, anradio-frequency (RF) generator, a digital-to-analog converter, anencoder, a driver for a backlight source of a liquid crystal panel usedfor the display of the mobile phone.

FIG. 13 is a partial cross-sectional view (a cross-sectional view of thefirst casing 112) of the mobile phone as shown in FIG. 12. Asemiconductor module 130 according to the sixth embodiment of thepresent invention is mounted on a printed circuit board 128 through theelectrodes 20, and electrically connected to the display 118 and thelike through the printed circuit board 128. The radiator 18 with theprojections is formed on the rear surface of the semiconductor module130 (the opposing surface to the electrodes 20). The radiator 18 comesinto contact with the first casing 112 at one surface thereof. Thisconfiguration allows heat generated by the semiconductor module 130 tobe effectively radiated out of the first casing 112 without filling thefirst casing 112 with the heat.

The portable device according to the sixth embodiment has the followingadvantages:

(17) The radiator 18 effectively radiates out heat of the semiconductormodule 130, thereby preventing the temperature of the semiconductormodule 130 from rising and thus reducing the thermal stress between there-wiring pattern 14 and the insulating layer 19 and the thermal stressbetween the radiator 18 and the insulating layer 17. Accordingly,separation of the re-wiring pattern 14 in the semiconductor module fromthe insulating layer 19, and separation of the radiator 18 from theinsulating layer 17 are prevented, thereby improving the reliability(heatproof reliability) of the semiconductor module 130. As a result, itis possible to improve the reliability (heatproof reliability) of theportable device.

(18) The semiconductor module 130, which is manufactured by the CSP(Chip Size Package) wafer process shown in the above embodiments, isthin and small, so that installing the semiconductor module 130 in aportable device allows the portable device to become thinner andsmaller.

The first embodiment shows the radiator 8 covering the entire rearsurface R of the semiconductor substrate 1, but the present invention isnot limited thereto. Alternatively, for example, the radiator 8 may bepatterned to selectively cover a specific region of the semiconductorsubstrate 1 as in the fifth embodiment. Even this modification has thesame advantages as those of the first embodiment, on regions where theradiator 8 and the projections 8 a located. The same modification isapplicable to the second embodiment, thereby providing the sameadvantages thereto.

The first embodiment shows the semiconductor module being manufacturedby dicing a semiconductor wafer together with the radiator 8 located inthe scribe lines 5, but the present invention is not limited thereto.Alternatively, for example, the semiconductor module may be manufacturedin such a way that the radiator 8 located in the scribe lines 5 isremoved by etching before dicing and then the semiconductor wafer isdivided into individual semiconductor modules by dicing. Thismodification reduces stress load caused by dicing of the radiator 8(stress load transmitting from the radiator 8 to the projections 8 a),thus reducing manufacturing variations of the semiconductor modules.Further to this, the manufacturing cost of the semiconductor module canbe reduced. The same is true for the second to the fifth embodiments.

The first embodiment shows the projections 8 a being arranged on theentire radiator 8 in a matrix array in plane, but the present inventionis not limited thereto. Alternatively, for example, the projections 8 amay be arranged on the radiator 8 at any positions in plane. Inparticular, if the projections 8 a are selectively arranged on a regionwhere the circuit element serving as a heater in the semiconductorsubstrate 1 is located, this modification allows effective heatradiation in the semiconductor module and thus improves the connectionreliability. The same is true for the second to the fifth embodiments.

The first embodiment shows the projections 8 a which are integrallyformed with the radiator 8 and come into direct contact with the rearsurface R of the semiconductor substrate 1, but the present invention isnot limited thereto. Alternatively, for example, the insulating layermay be partly interposed between the rear surface R of the semiconductorsubstrate 1 and the projections 8 a. This modification decreases theeffect of improving the heat radiation of the semiconductor module, butit leads to a reduction in the problems of separation of the radiator 8from the semiconductor substrate 1 and warpage (deformation) of thesemiconductor substrate 1 because the projections 8 a reduces thewarpage of the radiator 8 when compared with the conventionalsemiconductor module.

The second embodiment shows the press working in which the copper plate18 z integrally formed with the projections 18 a, and the copper plate14 z integrally formed with the projecting conductors 14 a aresimultaneously pressed against the semiconductor substrate 11.Alternatively, the copper plates may be subjected to two-step pressworking in such a way that one of the copper plates is subjected to apress working and the other copper plate is then subjected to anotherpress working. Even this modification has the same advantages as thoseof the second embodiment. Alternatively, the copper plate 18 zintegrally formed with the projections 18 a may be subjected to pressworking against the semiconductor wafer on which the re-wiring pattern 4of the first embodiment, as shown in FIG. 3B, has been formed, therebyforming the radiator 18. This modification has at least the advantagesof (5) to (8) described above.

The second embodiment shows the projections 18 a which each have a roundsection and which tapers toward the top portion 18 a 1, but the presentinvention is not limited thereto. Alternatively, for example, each ofthe projections 18 a may be a circular cylinder with a predetermineddiameter. The projections 18 a may each have a polygonal section such assquare. Even these modifications allow effective heat radiation throughthe projections in the semiconductor module, so that the projectionsimprove the connection reliability at those sites.

The third embodiment shows the projection 18 a and the recess 22 whichfits to the projection 18 a, but the present invention is not limitedthereto. Alternatively, for example, the projection 18 a (especially,its top portion) may be larger than the recess 22 (opening size). Thetop portions of the projections 18 a are crushed and thus change itsshape by the pressure during press working. In this case, eachprojection 18 a is embedded in each recess 22, and comes into contactwith its surrounding semiconductor substrate 11. Accordingly, thecontact areas between the projections 18 a and the semiconductorsubstrate 11 are further increased, and thus the connection reliabilityand heat radiation is increased. Conversely, when the projection 18 a(especially, its top portion) is smaller than the recess 22 (openingsize), the projections 18 a, even if crushed and thus changing its shapeby the pressure during press working, are all placed within the recesses22. As a result, it is possible to reduce variations in connectionreliability and heat radiation caused by variations in contact areas ofthe projections 18 a.

The third embodiment shows the recesses 22 corresponding to allprojections 18 a, respectively, but the present invention is not limitedthereto. Alternatively, for example, some of the projections 18 a may benot embedded in the recesses 22 for each of the semiconductor substrate11 in the semiconductor wafer. This configuration is achieved in such away that the recesses 22 are formed only on regions correspondingrespectively to some of the projections 18 a, and the heights of theprojections 18 a are adjusted accordingly. This modification has atleast the advantages of (12) to (14) described above, at least on theregions where the projections 18 a are embedded.

1. A semiconductor module comprising: a substrate consisting ofsemiconductive material with a first principal surface and a secondprincipal surface opposing the first principal surface; a circuitelement provided in at least a part of the substrate; an electrodeprovided on the first principal surface with the electrode beingelectrically connected to the circuit element; an insulating layerprovided on the second principal surface; a radiator provided on theinsulating layer; and a projection provided integrally with theradiator, with the projection penetrating the insulating layer toconnect to the second principal surface, wherein the radiator includespatterned regions and the insulating layer is exposed through anentirety of an area between the patterned regions of the radiator. 2.The semiconductor module according to claim 1, wherein a plurality ofthe projections is arranged on the radiator in a matrix array in plane.3. The semiconductor module according to claim 1, wherein a top of theprojection is embedded in the substrate.
 4. The semiconductor moduleaccording to claim 1, wherein a gap is formed between the insulatinglayer and the radiator, except for the projection.
 5. The semiconductormodule according to claim 1, wherein the radiator is patterned so as toselectively cover a specific region of the substrate.
 6. Thesemiconductor module according to claim 1, wherein: the insulating layeris made of an insulating resin which is a material that undergoesplastic flow when placed under pressure; and the projection penetratesthe insulating layer by compression-bonding the radiator onto theinsulating layer to thermally connect the projection to the circuitelement.
 7. The semiconductor module according to claim 2, wherein: theinsulating layer is made of an insulating resin which is a material thatundergoes plastic flow when placed under pressure; and the projectionspenetrate the insulating layer by compression-bonding the radiator ontothe insulating layer to thermally connect the projections to the circuitelement.
 8. The semiconductor module according to claim 3, wherein: theinsulating layer is made of an insulating resin which is a material thatundergoes plastic flow when placed under pressure; and the projectionpenetrates the insulating layer by compression-bonding the radiator ontothe insulating layer to thermally connect the projection to the circuitelement.
 9. The semiconductor module according to claim 4, wherein: theinsulating layer is made of an insulating resin which is a material thatundergoes plastic flow when placed under pressure; and the projectionpenetrates the insulating layer by compression-bonding the radiator ontothe insulating layer to thermally connect the projection to the circuitelement.
 10. The semiconductor module according to claim 5, wherein: theinsulating layer is made of an insulating resin which is a material thatundergoes plastic flow when placed under pressure; and the projectionpenetrates the insulating layer by compression-bonding the radiator ontothe insulating layer to thermally connect the projection to the circuitelement.
 11. A portable device comprising: a casing; and thesemiconductor module according to any one of claims 1 to 10, thesemiconductor module being housed in the casing.
 12. The portable deviceaccording to claim 11, wherein the radiator of the semiconductor modulecomes into contact with an inner surface of the casing.